Tranny swap

[Redog]

Found out today that my tranny pump isn't keeping a good pressure at all times. My mech said the pump is on the way out, so I'm looking right now at a new or used transmission. Used installed would be $1000 with a short warranty (30 days to 6 months) and new would be $2900 with a 3 year 36,000 mile warranty. Thinking the new, but it depends on WHEN it goes and what the wallet sasys at that time

I know I have the 4T45 transmission, and I also know that the GAGT Tranny has a 3.29 FDR and the Cobalt, Ion, G6 base, etc have the 3.63 FDR

Two questions:

1 Which would be the better FDR for my car? I googled FDR's and found that the calc's aren't that far off using 3.05 FDR, with a 25 inch tire at 70 MPH I came up with 2009 RPM's which is pretty damn close if not dead on. I like the 3.29 but thinking the quickeness of a 3.63 would be just simply

2 If I did the 3.63 FDR, all those trannies are mated to 4 bangers. Are the clutch packs, tranny pump, gears, etc able to handle a V6 motor, or did GM used weaker items to save money?
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[Redog]

Keep in mind I'm going to be doing an engine build with a WOT-TECH Street/Strip cam

Specs of cam:

WOT-TECH web site

• 259/265 adv duration
• 210/216 .050" duration
• .506"/.506" lift @ 1.6:1 Rocker Ratio
• 113 Intake Center Line
• 114 Lobe Seperation Angle

[JLw7123]

i know this is of topic but have you thought of swaping in the 4T65e-HD from the grand prix.

Just as a comparison Ken, my trans has a 3.42FDR and the motor is turning ~2000rpm @ 60mph. 70mph is ~2300rpm.

[Redog]

^^ Hmmmm, I'm guessing that a 3.63 might be a little too high for my cruising tastes. 2300 @ 70 would be good.


What car had a 3.42 FDR? I'm not going to be doing a rebuild, just a swap

i know this is of topic but have you thought of swaping in the 4T65e-HD from the grand prix

After the problems Bdyman had, no way

[03Sleepr]

Originally Posted by Redog

^^ Hmmmm, I'm guessing that a 3.63 might be a little too high for my cruising tastes. 2300 @ 70 would be good.


What car had a 3.42 FDR? I'm not going to be doing a rebuild, just a swap



After the problems Bdyman had, no way

what problems did he have?

Bdyman also had an LS4....a bit more power in a much heavier car.

I had my transmission rebuilt with different drive/driven gears. The LD9/4T40-E Alero came with this gearset.

[Redog]

How good are those gears/clutches/etc in stock form in the 4T40.

It's the same case, right

[Redog]

Originally Posted by 03Sleepr

what problems did he have?

I know he blew 2 transmissions, maybe 3 or 4, with normal driving and in was a common problem for that car

Not really looking at the fab work, IDK, it all depends on when this trany goes, I just like to have options

Originally Posted by Redog

How good are those gears/clutches/etc in stock form in the 4T40.

It's the same case, right

I couldn't say......when I had the gears replaced, I did a new chain, Blue Plate clutches, new steels, and billet accumulator pistons.

[Redog]

What did that run?

I'm pretty much looking for something that will also match my new cam which I have listed above. Matt the heads I bought off you will work nicely with that cam, but I also want to get the proper gearing and convertor for it. The convertor can be replaced at the engine build

[01GrandAm]

If you are looking to do it on the cheap, find a low mileage 4t45e out of a 03-05 Grand Am GT (3.29 ratio). I picked up a used 4t45e out of a 04 gagt in MI that had 25K miles for $150 a few months ago. It was missing the torque converter, but I had one in the garage so I was good to go.

[Redog]

I actually took a peek at car-part.com and found one not too far away out of a 05 GAGT with only 3,385 miles on it Somehow I doubt that mileage

Seen others on there fairly inexpensive

[jawa]

what are the advantages of grabing a gagt tranny instead of a alero one?
the alero being a 6 cyl

[zzyzzx]

I don't know about Alero's, but on my 1995 Ford Escort the transmission's oil pump is externally mounted and actually pretty easy to get to once you have removed a wheel and a splash shield. It would not be much of a problem to replace just the transmission oil pump on that car. It's that rusty thing pictured here:

[Cliff8928]

Ever think about going with a higher stall converter? Maybe one from like a 2200 J-Body?

[Redog]

Well I'm going to need a high stall convertor anyway.

What's the stock convertor stall anyway

[Cliff8928]

Not sure what it is, but the "73CW" is the highest stall factory converter you can get with the woven carbon lining....

[billytheman1188]

I like this thread....cause my tranny is starting to poop the bed and i want to rebuild it but make it able to handle the abuse i want to put on it in the future :P I will be keeping a CLOSE eye on this thread

[zzyzzx]

Isn't there a way you can make the existing transmission oil pump increase the oil pressure by putting in a stronger spring? I've seen threads about it (not here) and for my Escort there is a TSB on it with a revised valve and spring.